[WIP] Kerbal Fuels: Stock Compatability with Real Fuels-ish volumes and masses.

[SorensonPA]

What's this mod about?

NathanKell's Real Fuels mod is absolutely essential for satisfactory use of the much-beloved Real Solar Systems mod, and goes to great lengths to create as accurate a portrayal as possible of the numerous propellant and propellant tank types developed over the course of aerospace research. This accuracy, one of Real Fuels' greatest strengths, is also one of its greatest weaknesses: due to the considerable amount of scripting involved in Real Fuels and mods dependent upon it, many other mods which have a tentative overlap in their area of interest - TweakScale, for example - are rendered inert or suffer from serious malfunction.

What would this mod do?

The goal of Kerbal Fuels is to modify stock fuel and engine assets in such a way as to replicate many of the characteristics of Real Fuels that make it essential for Real Solar System, but maintain enough of the stock character and functionality that it maintains (a reasonable chance of) comparability with as many mods as possible and require only a minimum of effort to bring others into alignment.

There are three distinct factors that define Real Fuels and make it necessary for any kind of Real Solar System playthrough: realistic fuel types, realistic fuel tanks and realistic engines. The resource and plugin data that forms much of the backbone of these factors is what can lead to conflicts, but a reasonable facsimile of those basic characteristics can be applied to get something of an approximation of that functionality:

• Give resources like Liquid Fuel and Oxidizer appropriate densities and volumes, thus allowing for rockets of realistic scales
  
• Give fuel tanks realistic volumes and tank mass as a percentage of fuel mass, thus giving a realistic approximation of total tank weight
  
• Give engines proper mass values based upon their thrust and isp levels to give a realistic approximation of performance, while refraining from adjusting other values to maintain stock "character"
  

What would this mod NOT do?

While Real Fuels and its dependent mods deserve praise for their dedication to create as authentic a space program management experience as possible, the lengths to which they go to create this authenticity can leave many mods in a lurch as far as cohabitation goes. With this in mind, while Kerbal Fuels seeks to replicate Real Fuels' core characteristics, it stops short of more exhaustive measures of doing so in order to avoid burning certain bridges. As such, Kerbal Fuels will not:

• Add new resources and fuel types, and the necessary scripting to make them accessible and functional: new resources would require a heavy dose of engine modification, which is part of the root of Real Fuels' conflicts with other mods
  
• Add new fuel tank types and characteristics, and the necessary scripting to make them accessible and functional, which is likewise part of the root of mod conflicts
  
• Modify engine characteristics other than mass, save rare situations like the Twin Boar booster which includes fuel tank functionality, as some of these characteristic changes would hinge upon having new resources and fuel tank types, already ruled out (increasing vacuum isp to ~420 which would only be possible with a LH2/LOX fuel, LV-Ns and other special cases aside)
  
• Provide highly-scrutenous levels of accuracy and real-life replication. The goal of Kerbal Fuels is to create an approximation while still keeping certain stock characteristics and to do so with a minimum of risk of mod conflict, so while obviously the LV-N wouldn't be running purely on the KSP analogue of RP-1 it's a relatively minor liberty/abstraction that has to be tolerated since setting the proper fuel source would create bigger problems that're anathema to the core purpose of the mod.
  

So where's the mod?

Kerbal Fuels can be downloaded from Kerbal Stuff and will hopefully be available through CKAN shortly. Procedural Parts and Module Manager are required for Kerbal Fuels to function.

Given this is currently a test-of-concept stage, Kerbal Fuels modifies only stock LFO and MonoPropellant engines, though should this prove a feasible idea other popular engine pack mods will be incorporated.

So how does it work?

Surprisingly well. Between Procedural Parts and TweakScale, Kerbal Fuels can create basic replications of early space flights and their launch vehicles with approximately similar end results, such as a ~140-ton rocket capable of delivering a ~4-ton crew capsule to orbit with sufficient fuel to de-orbit and land. Given the lack of proper LH2/LOX engines and their ~420 isp, though, lunar missions and beyond are likely to prove challenging, although the LV-N might be able to compensate for such.

So what do you want?

Feedback, naturally. Suggestions on data sources, part analogues, empty and full mass-to-volume and fuel-volume-to-tank-volume ratios. Much of this initial setup was hobbled together from Real Fuels itself, though the methodology is not as perfect as desired, and getting access to some original sources and figures and insight from people who know a hell of a lot more about real rocketry would make things much better.

Changelog:

0.1: Initial fully-compiled version.

Raw .cfg dump, Fuel Tanks:

@PART[adapterMk3-Mk2]
{
    @Mass = 0.29
    @RESOURCE[LiquidFuel]
    {
        @amount = 4500
		@maxAmount = 4500
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 5500
       @maxAmount = 5500
    }
}

@PART[adapterMk3-Size2]
{
    @Mass = 0.362
    @RESOURCE[LiquidFuel]
    {
       @amount = 5625
       @maxAmount = 5625
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 6875
       @maxAmount = 6875
    }
}

@PART[adapterMk3-Size2Slant]
{
    @Mass = 0.362
    @RESOURCE[LiquidFuel]
    {
       @amount = 5625
	   @maxAmount = 5625
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 6875
       @maxAmount = 6875
    }
}

@PART[adapterSize2-Mk2]
{
    @Mass = 0.116
    @RESOURCE[LiquidFuel]
    {
       @amount = 1800
	   @maxAmount = 1800
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 2200
       @maxAmount = 2200
    }
}

@PART[adapterSize2-Size1]
{
    @Mass = 0.116
    @RESOURCE[LiquidFuel]
    {
       @amount = 1800
	   @maxAmount = 1800
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 2200
       @maxAmount = 2200
    }
}

@PART[adapterSize2-Size1Slant]
{
    @Mass = 0.116
    @RESOURCE[LiquidFuel]
    {
       @amount = 1800
	   @maxAmount = 1800
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 2200
       @maxAmount = 2200
    }
}

@PART[adapterSize3-Mk3]
{
    @Mass = 0.29
    @RESOURCE[LiquidFuel]
    {
       @amount = 4500
	   @maxAmount = 4500
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 5500
       @maxAmount = 5500
    }
}

@PART[miniFuelTank]
{
    @Mass = 0.003
    @RESOURCE[LiquidFuel]
    {
       @amount = 90
	   @maxAmount = 90
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 110
       @maxAmount = 110
    }
}

@PART[mk2_1m_AdapterLong]
{
    @Mass = 0.116
    @RESOURCE[LiquidFuel]
    {
       @amount = 1800
	   @maxAmount = 1800
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 2200
       @maxAmount = 2200
    }
}

@PART[mk2_1m_Bicoupler]
{
    @Mass = 0.058
    @RESOURCE[LiquidFuel]
    {
       @amount = 900
	   @maxAmount = 900
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 1100
       @maxAmount = 1100
    }
}

@PART[mk2Fuselage]
{
    @Mass = 0.116
    @RESOURCE[LiquidFuel]
    {
       @amount = 4000
	   @maxAmount = 4000
    }
}

@PART[mk2FuselageLongLFO]
{
    @Mass = 0.116
    @RESOURCE[LiquidFuel]
    {
       @amount = 1800
	   @maxAmount = 1800
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 2200
       @maxAmount = 2200
    }
}

@PART[mk2FuselageShortLiquid]
{
    @Mass = 0.058
    @RESOURCE[LiquidFuel]
    {
       @amount = 2000
	   @maxAmount = 2000
    }
}

@PART[mk2FuselageShortLFO]
{
    @Mass = 0.058
    @RESOURCE[LiquidFuel]
    {
       @amount = 900
	   @maxAmount = 900
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 1100
       @maxAmount = 1100
    }
}

@PART[mk2FuselageShortMono]
{
    @Mass = 0.043
    @RESOURCE[MonoPropellant]
    {
       @amount = 1600
	   @maxAmount = 1600
    }
}

@PART[mk2SpacePlaneAdapter]
{
    @Mass = 0.058
    @RESOURCE[LiquidFuel]
    {
       @amount = 900
	   @maxAmount = 900
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 1100
       @maxAmount = 1100
    }
}

@PART[mk3FuselageLF_25]
{
    @Mass = 0.363
    @RESOURCE[LiquidFuel]
    {
       @amount = 12500
	   @maxAmount = 12500
    }
}

@PART[mk3FuselageLF_50]
{
    @Mass = 0.726
    @RESOURCE[LiquidFuel]
    {
       @amount = 25000
	   @maxAmount = 25000
    }
}

@PART[mk3FuselageLF_100]
{
    @Mass = 1.452
    @RESOURCE[LiquidFuel]
    {
       @amount = 50000
	   @maxAmount = 50000
    }
}

@PART[mk3FuselageLFO_25]
{
    @Mass = 0.363
    @RESOURCE[LiquidFuel]
    {
       @amount = 5625
	   @maxAmount = 5625
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 6875
       @maxAmount = 6875
    }
}

@PART[mk3FuselageLFO_50]
{
    @Mass = 0.726
    @RESOURCE[LiquidFuel]
    {
       @amount = 11250
	   @maxAmount = 11250
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 13750
       @maxAmount = 13750
    }
}

@PART[mk3FuselageLFO_100]
{
    @Mass = 1.452
    @RESOURCE[LiquidFuel]
    {
       @amount = 22500
	   @maxAmount = 22500
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 27500
       @maxAmount = 27500
    }
}

@PART[mk3FuselageMONO]
{
    @Mass = 0.169
    @RESOURCE[MonoPropellant]
    {
       @amount = 6250
	   @maxAmount = 6250
    }
}

@PART[proceduralTankLiquid]
{
    @MODULE[TankContentSwitcher]
    {
        @TANK_TYPE_OPTION[Mixed]
        {
            @dryDensity = 0.029
            @RESOURCE[LiquidFuel]
            {
				@unitsPerT = 15516
            }
            @RESOURCE[Oxidizer]
            {
				@unitsPerT = 18964
            }
        }
        @TANK_TYPE_OPTION[LiquidFuel]
        {
            @dryDensity = 0.029
            @RESOURCE[LiquidFuel]
            {
				@unitsPerT = 34480
            }
        }
        @TANK_TYPE_OPTION[Oxidizer]
        {
            @dryDensity = 0.029
            @RESOURCE[Oxidizer]
            {
				@unitsPerT = 34480
            }
        }
    }
}

@PART[proceduralTankOre]
{
    @MODULE[TankContentSwitcher]
    {
        @TANK_TYPE_OPTION[Ore]
        {
            @RESOURCE[Ore]
            {
				@unitsPerT = 866.434
            }
        }
    }
}

@PART[proceduralTankRCS] //Based on tank mass ratios for hypergolic fuels like Aerozine50+NTO: Monoprop density is more akin to straight Hydrazine, but Hydrazine tank mass ratios (restricted to Service Module types) are much higher and would kill its usage for actual hypergolic engines.
{
    @MODULE[TankContentSwitcher]
    {
        @TANK_TYPE_OPTION[RCS]
        {
            @dryDensity = 0.027
            @RESOURCE[MonoPropellant]
            {
				@unitsPerT = 36275.257
            }
        }
    }
}

@PART[proceduralTankXenon] //
{
    @MODULE[TankContentSwitcher]
    {
        @TANK_TYPE_OPTION[XenonGas]
        {
            @dryDensity = 0.0908
            @RESOURCE[XenonGas]
            {
				@unitsPerT = 110132.158
            }
        }
    }
}

@PART[radialRCSTank]
{
    @Mass = 0.002
    @RESOURCE[MonoPropellant]
    {
       @amount = 76
	   @maxAmount = 76
    }
}

@PART[rcsTankRadialLong]
{
    @Mass = 0.006
    @RESOURCE[MonoPropellant]
    {
       @amount = 240
	   @maxAmount = 240
    }
}

@PART[toroidalFuelTank]
{
    @Mass = 0.008
    @RESOURCE[LiquidFuel]
    {
       @amount = 135
		@maxAmount = 135
    }
    @RESOURCE[Oxidizer]
    {
       @amount = 165
        @maxAmount = 165
    }
}

@PART[xenonTankRadial]
{
    @Mass = 0.003
    @RESOURCE[MonoPropellant]
    {
       @amount = 400
	   @maxAmount = 400
    }
}

Resources:

@RESOURCE_DEFINITION[LiquidFuel] //RP-1 analogue
{
	@density = 0.000859
	@unitCost *= 0.18
}

@RESOURCE_DEFINITION[Oxidizer] //Standard Liquid Oxygen, stock multiplier 3.9177277179236043095004897159647
{
	@density = 0.001141
	@unitCost *= 0.036
}

@RESOURCE_DEFINITION[MonoPropellant] //Based on density of Hydrazine
{
	@density = 0.001021
	@unitCost *= 0.24
}

//Xenon density/price isn't being changed (yet) due to the relationship between Xenon and EC for providing thrust, as changing density could drastically increase or decrease the EC requirement and its feasibility along with it. Based on RL density KSP Xenon units are ~0.03225806451612903225806451612903 of a liter

//@RESOURCE_DEFINITION[XenonGas]
//{
	//@density = 0.0031
	//@unitCost *= 4
//}

@RESOURCE_DEFINITION[IntakeAir]
{
	@density = 0.001
	@unitCost *= 0.2
}

Engines:

@PART[liquidEngine] //LV-T30 Reliant, based on Aerojet A-7 TWR of 64.2112462006079. 
{
    @mass = 0.340
}
@PART[liquidEngine2] //LV-T45 Swivel, based on Bell 8081 TWR of 55.8230769230769
{
    @mass = 0.368
}
@PART[engineLargeSkipper] //Skipper, based on Aerojet LR-91-5 TWR of 90.71
{
    @mass = 0.717
}

@PART[liquidEngine1-2] //Mainsail, based on Aerojet LR-87-3 TWR of 89.204410011919
{
    @mass = 1.682
}

@PART[liquidEngine2-2] //Poodle, based on J-2 TWR of 73.1801112656467 * 1.2028571428571428571428571428571 = 88.025219550963601999999999999997to compensate for lower vac isp (421/350)
{
    @mass = 0.284
}

@PART[liquidEngine3] //Terrier, based on Rocketdyne RS-72 TWR of 40.922454165373989865413878178138
{
    @mass = 0.147
}

@PART[liquidEngineMini] //Spark, based on Notional Liberty-2 TWR of 44.34
{
    @mass = 0.040
}

@PART[microEngine] //LV-1 Ant, based on Marquardt R-40A TWR of 38.43
{
    @mass = 0.005
}

@PART[nuclearEngine] //LV-N, based on US Dept. of Energy Nerva NTR 1971 total launcher TWR of 2.5991651424389902159071088144992 (Nerva NTR 1991, which has an actual engine-specific mass of ~8,500 kg, has a pure engine TWR of 3.9983210409546081429513701505067, but since Kerbal Fuels doesn't account for increased cryo tank mass for storing actual LH2 the lower ratio is used to simulate)
{
    @mass = 2.106
}

@PART[omsEngine] //Puff, based on AJ10-118k TWR of 45.143439638852482889180136886559 as data on the AJ10-190 used in the STS OMS was unavailable
{
    @mass = 0.043
}

@PART[radialEngineMini] //LV-1R Spider, based on Marquardt R-40A TWR of 38.43
{
    @mass = 0.0052
}

@PART[radialLiquidEngine1-2] //Thud, based on Rocketdyne RS-78 TWR of 40.922454165373989865413878178138
{
    @mass = 0.293
}

@PART[Size2LFB] //Twin Boar, based on SpaceX Merlin 1-C TWR of ~96
{
    @mass = 3.425
	@RESOURCE[LiquidFuel]
    {
		@amount = 14400
		@maxAmount = 14400
	}
	@RESOURCE[Oxidizer]
    {
		@amount = 17600
		@maxAmount = 17600
	}
}

@PART[Size3AdvancedEngine] //Rhino, based on Merlin 1-D Vacuum TWR of ~150
{
    @mass = 1.334
}

@PART[Size3EngineCluster] //Mammoth, based on F-1 Cluster TWR of 94.0680252651651
{
    @mass = 4.252
}

@PART[smallRadialEngine] //Twitch, based on Rocketdyne ATE TWR of 35.1506204084502
{
    @mass = 0.045
}

@PART[toroidalAerospike] //Aerospike, based on proposed US Air Force Institute of Technology DEAN TWR of ~106.5
{
    @mass = 0.106
}

Kerbal Fuels is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) license.

Edited June 26, 2015 by SorensonPA

[NathanKell]

Or I could just get off my duff and add tweakscale support. :]

Not that I don't think this a good idea, but it reminds me I really ought to fix that.

[SorensonPA]

First pass is completed: all LFO/Mono engines given TWRs based on approximate real-life analogues, Mk. 2 and 3 fuselages updated, just realized the Mk. 1 Intake/Fuselage is not. Contemplating a company-pairing approach for finding analogues: Aerojet for Jeb's, Kosberg/Glushko for Rockomax, Aerojet-Rocketdyne for Kerbodyne, though I suspect this could hinder as much as help.

Edited June 25, 2015 by SorensonPA

[NathanKell]

Cool!

The KR-2L is clearly the J-2X and the Mammoth is clearly 4x SSME, and the Twin Boar is clearly the Pyrios booster. Other than that KSP doesn't really do analogues, excepting perhaps the OMS. So you're on your own there.

RF 10.4 supports tweakscale btw if you want to try that.